The nasal mucosa is the main gateway for entry, replication and elimination of the SARS-CoV-2 virus, the pathogen that causes severe acute respiratory syndrome (COVID-19). The presence of the virus in the epithelium causes damage to the nasal mucosa and compromises mucociliary clearance. The aim of this study was to investigate the presence of SARS-CoV-2 viral antigens in the nasal mucociliary mucosa of patients with a history of mild COVID-19 and persistent inflammatory rhinopathy. We evaluated eight adults without previous nasal diseases and with a history of COVID-19 and persistent olfactory dysfunction for more than 80 days after diagnosis of SARS-CoV-2 infection. Samples of the nasal mucosa were collected via brushing of the middle nasal concha. The detection of viral antigens was performed using immunofluorescence through confocal microscopy. Viral antigens were detected in the nasal mucosa of all patients. Persistent anosmia was observed in four patients. Our findings suggest that persistent SARS-CoV-2 antigens in the nasal mucosa of mild COVID-19 patients may lead to inflammatory rhinopathy and prolonged or relapsing anosmia. This study sheds light on the potential mechanisms underlying persistent symptoms of COVID-19 and highlights the importance of monitoring patients with persistent anosmia and nasal-related symptoms.

Background: Actinobacteria are major producers of antibacterial and antifungal metabolites and are growing their search for substances of biotechnological interest, especially for use in agriculture, among other applications. The Amazon is potentially rich in actinobacteria; however, almost no research studies exist. Thus, we present a study of the occurrence and antifungal potential of actinobacteria from the rhizosphere of Inga edulis, a native South American plant and one that is economically useful in the whole of the Amazon. Methods: Among the 64 actinobacteria strains isolated from the rhizosphere of three Inga edulis plants, 20 strains were selected and submitted to dual-culture assays against five important phytopathogenic fungi and morphological and 16S rRNA gene analyses. Two strains, LaBMicrA B270 and B280, were also studied for production curves of metabolic extracts and antifungal activities, including their minimum inhibitory concentration (MIC) against phytopathogenic fungi. Results: Among the 20 strains, 90% were identified as Streptomyces and 10% as Kitasatospora. All the strains showed antagonisms against two or more of five phytopathogens: Corynespora cassiicola, Colletotrichum guaranicola, Colletotrichum sp., Pestalotiopsis sp., and Sclerotium coffeicola. Streptomyces spp. strains LaBMicrA B270 and B280 were active against phytopathogens of the guarana plant (Paullinia cupana). Furthermore, AcOEt/2-propanol 9:1 extract from the 10-day strain LaBMicrA B280 cultured medium presented activity against all the phytopathogens tested, with a minimum inhibitory concentration of 125 μg/mL. Conclusions: The results revealed various actinomycetes in three rhizospheres of I. edulis in the Amazon and the high potential of metabolic extracts from some of these bacterial strains against phytopathogenic fungi that destroy numerous crops.

Epstein-Barr virus (EBV) and cytomegalovirus (CMV) are viruses globally distributed that have been associated with the development and prognosis of many pathologies, including hematological diseases. This study aimed to characterize the epidemiological profile of EBV infection and the infection-correlated hepatic manifestations in patients with hematological diseases of the northern Brazilian state of Amazonas. A total of 228 patients were serologically tested for the presence of anti-EBV and anti-CMV IgG antibodies through an enzyme-linked immunosorbent assay. The coinfection with CMV, sociodemographic and laboratory records of all patients were also assessed. The overall prevalence observed among the study population for EBV infection and EBV/CMV coinfection was 85.09% (95% CI: 0.80–0.90) and 78.51% (95% CI: 0.73–0.84), respectively. The age group 31–40 years old were more susceptible to EBV/CMV coinfection (95% CI: 1.59–93.41, p = 0.011), while young people aged 1–10 years old were less affected for both EBV infection (CI 95%; 0.66–0.91, p = 0.001) and EBV/CMV coinfection (95% CI: 0.52–0.81, p < 0.0001). High serum levels of the liver biomarker ferritin were associated with EBV infection (95% CI: 1.03–1.54, p = 0.031) and EBV/CMV coinfection (95% CI: 1.02–1.70, p = 0.038). Our findings indicated that the elevated prevalence of EBV infection is not associated with the hematological diseases or transfusion rates, but with the socioeconomic status of the study population. Also, this study suggests that the EBV infection and its coinfection with CMV are related to the increase of serum ferritin levels.

Aim: To assess oral microbial status in patients with acute lymphoblastic leukemia (ALL) undergoing high-dose chemotherapy and to unravel possible associations between nosocomial pathogens and the establishment of chemotherapy-induced oral mucositis (CIOM). Methods: Oral mucosa, saliva, and peripheral blood samples were collected from 46 ALL subjects one day prior to chemotherapy (D0) and 2 weeks after treatment initiation (D14). Clinical intraoral inspection was performed by a single practitioner, with mucositis classification performed according to the WHO oral toxicity scale. Blood components were quantified by automatic flow cytometry, while oral Staphylococcus aureus and Pseudomonas aeruginosa were detected by Polymerase Chain Reaction with species-specific primers. Associations among bacteria and clinical findings were determined by Fisher’s Exact test, longitudinal bacterial changes by paired Macnemar, and correlations among blood parameters and mucositis status or bacteria via Mann-Whitney. Results: S. aureus displayed higher detection rates at D14 (p < 0.05) and was positively associated with mucositis, adoption of a non-solid diet (all p < 0.001), nausea and fever (all p < 0.05). Conversely, P. aeruginosa did not correlate to CIOM clinical parameters. At the systemic standpoint, lower hemoglobin levels associated with CIOM and fever events (all p < 0.01). Conclusion: The study evidences S. aureus as a potential pathogen in ALL-CIOM, reaffirming microbial control as an important preventive measure during high-dose immunosuppressive therapy. The weight of non-white-blood-cell parameters should be validated as novel CIOM biomarkers in prospective research.

This work evaluates the enzymatic production of hydrolases and oxireductases by endophytic fungi isolated from leaves of the caesarweed (Urena lobata L.), which is a perennial plant that is well adapted to the Amazon floodplains region, being and is widely used in the production of hessian sacks and other products of natural fiber. Fungi strains Fusarium sp. (1290) and Corynespora sp. (1291) were reactivated, and had their DNA extracted and sequenced to obtain molecular identification. For enzymatic production, dried and ground caesarweed was used as a substrate in the mineral salt solutions Manachini and GLBN 40 over during 10 days of submerged cultivation (CS) under agitation. The CA was vacuum filtered daily with a 0.22 µm Millipore membrane to obtain enzymatic extracts, from which the activities of FPase, xylanase, CMCase, β-glycosidase, pectinase, laccase, manganese peroxidase (MnP) and lignin peroxidase (LiP) were evaluated. Lines strains 1290 and 1291 were identified as F. pseudocircinatum and C. torulosa, respectively, the latter being the best producer of laccase (8,691 U/L), MnP (5,353 U/L), β-glycosidase (0.328 U/mL) and CMCase (0.351 U/mL) and the fungus F. pseudocircinatum was the best producer of FPase (1.294 U/mL), xylanase (12.052 U/mL) and pectinase (0.183 U/mL). No LiP activity was detected for either of the strains. The results showed that the strains used are promising for the production of seven of the eight quantified enzymes, and these enzymes are of interest to several industrial sectors.